Growth in two common gardens reveals species by environment interaction in carbon isotope discrimination of Eucalyptus.

TURNER, NEIL C.; SCHULZE, ERNST-DETLEF; NICOLLE, DEAN; KUHLMANN, IRIS

One-year-old sun leaves of 60 species of Eucalyptus were collected in August 2005 at an arboretum in South Australia with a mean annual rainfall of 427 mm, and 14 of the same species were sampled at an arboretum in Western Australia with a mean annual rainfall of 216 mm. We determined the genetic and phenotypic variation in carbon isotope composition (δ13C), specific leaf area (SLA) and nitrogen content per unit area of the species at each site. There were very significant (P < 0.001) differences in δ13C among the species at both sites. The mean δ13C of the 60 species at the wetter site was −27.6‰ (from −25.8‰ in Eucalyptus youngiana to −29.9‰ in Eucalyptus salicola) and of the 14 species at the drier site was −25.3‰ (from −23.7‰ in Eucalyptus ravida to −27.3‰ in Eucalyptus ewartiana). Of the 14 species common to both sites, four species had similar values of δ13C at the two sites despite the differences in rainfall, whereas in others the values of δ13C were significantly (P < 0.001) lower (more negative) at the wet than at the dry site. The SLA and nitrogen content per unit leaf area also differed significantly among the species (P < 0.001), but there was not a common relationship between δ13C and SLA or between δ13C and nitrogen content at the two sites. The strong species by environment interaction resulted from some species demonstrating phenotypic plasticity for δ13C, while others were inherently stable across environments.

AUSTRALIA; EUCALYPTUS; ISOTOPES; PLANT water requirements; PLANT-water relationships; NITROGEN; ARBORETUMS

Tree Physiology, 2010, Vol 30, Issue 6, p741

0829-318X

Academic Journal

10.1093/treephys/tpq029